Implemented rewrite middleware

Signed-off-by: Vishal Rana <vr@labstack.com>

middleware/rewrite_test.go

@@ -0,0 +1,35 @@
+package middleware
+
+import (
+	"net/http/httptest"
+	"testing"
+
+	"github.com/labstack/echo"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestRewrite(t *testing.T) {
+	e := echo.New()
+	e.Use(RewriteWithConfig(RewriteConfig{
+		Rules: map[string]string{
+			"/old":              "/new",
+			"/api/*":            "/$1",
+			"/js/*":             "/public/javascripts/$1",
+			"/users/*/orders/*": "/user/$1/order/$2",
+		},
+	}))
+	req := httptest.NewRequest(echo.GET, "/", nil)
+	rec := httptest.NewRecorder()
+	req.URL.Path = "/api/users"
+	e.ServeHTTP(rec, req)
+	assert.Equal(t, "/users", req.URL.Path)
+	req.URL.Path = "/js/main.js"
+	e.ServeHTTP(rec, req)
+	assert.Equal(t, "/public/javascripts/main.js", req.URL.Path)
+	req.URL.Path = "/old"
+	e.ServeHTTP(rec, req)
+	assert.Equal(t, "/new", req.URL.Path)
+	req.URL.Path = "/users/jack/orders/1"
+	e.ServeHTTP(rec, req)
+	assert.Equal(t, "/user/jack/order/1", req.URL.Path)
+}